Pilot Study of Raltegravir, an Integrase Inhibitor, in Human T-Cell Lymphotrophic Virus-1(HTLV-1) Associated Myelopathy, Tropical Spastic Paraparesis (HAM/TSP)
In this pilot study, we wish to determine the effects of Raltegravir, a clinically approved
HIV-1 integrase inhibitor, on HTLV-1 proviral load (PVL) in patients with HTLV-1 associated
myelopathy / tropical spastic paraparesis (HAM/TSP). We will also provide safety and
tolerability information on Raltegravir use in this condition and examine the correlation of
immune activation markers in HAM/TSP with the effects of Raltegravir on the PVL.
HAM/TSP, a relentlessly progressive and disabling myelopathy, occurs in up to 3% of HTLV-1
infected subjects. It results from immune-mediated bystander damage of the neural tissues in
association with an elevated PVL. In fact, a high PVL is considered to be the main risk
factor for developing HAM/TSP as the risk of disease rises exponentially once the PVL
exceeds 1 %. Currently there is no effective treatment for HAM/TSP.
There is evidence that active HTLV-1 replication, through the retroviral life cycle with new
virus integration, is occurring in vivo and contributes to the total HTLV-1 PVL in infected
subjects. Recently it was shown that Raltegravir could inhibit cell-free and cell-to-cell
transmission of HTLV-1 in vitro. Given the substantial clinical experience with its use in
HIV-1 infection and particularly its excellent safety profile, this agent is an attractive
therapeutic option for patients with HAM/TSP, either alone or in combination with
immunomodulatory treatment. In this pilot study we wish to determine the effects of
Raltegravir in vivo on HTLV-1 PVL and immune activation markers in patients with HAM/TSP.
In this 15 months single center, single arm, open label, baseline versus treatment pilot
clinical trial, sixteen subjects with HAM/TSP will receive Raltegravir at 400mg by mouth
twice daily in an initial 6 months treatment phase, followed by an additional 9 months post
treatment phase. Outcome measures will be collected every 3 months for the duration of the
The primary outcome measure is HTLV-1 proviral load, which will be measured by quantitative
PCR. Secondary outcome measures include safety and tolerability of Raltegravir, which will
be assessed by clinical exam and standardized neurological disability scales as well as
clinical laboratory studies. In addition, viral and immunologic outcome measures
investigating the impact of Raltegravir on HTLV-1 biology and its effects on immune function
will be measured including HTLV-1 proviral load in different lymphocyte populations, the
number of long terminal repeat (LTR) circles and HTLV-1 mRNA expression levels in freshly
isolated PBMC, assays of spontaneous lymphoproliferation and T-cell phenotype analysis.
Allocation: Non-Randomized, Endpoint Classification: Efficacy Study, Intervention Model: Single Group Assignment, Masking: Open Label, Primary Purpose: Treatment
Determine the effect of Raltegravir on HTLV-1 Proviral load in HAM/TSP patients
Steven Jacobson, Ph.D.
National Institute of Neurological Disorders and Stroke (NINDS)
United States: Federal Government
|National Institutes of Health Clinical Center, 9000 Rockville Pike||Bethesda, Maryland 20892|